IpodLinux On A Ipod Nano... Is It Safe...

No no and no. The worst thing you can do is actually MELT your iPod. The best way to fix is not to start with it.

Melt as in if you cook it. It'll turn in to an ingot of metal.

Is there any risks...
Yes, there's definitely risks.

I Read about a way to go into disk mode if your ipod is screwed up... and You Will Then Be able to Restore it in Disk Mode with the Ipod Updater...
Some users have reported that this is an effective way to return your iPod back to factory settings. Other have reported that this doesn't work at all.

And If a third Party Group Can play video on the Ipod why wont apple release a Firmware upgrade that allows playback of video... I know they Can...
Have you seen the video? It's garbage quality, and it there are barely any codecs compatible with it. It's the equivalent of watching a VHS qualiy videocasette on a 1" screen. Many times, you can't even get the audio and video to sync up properly.
The iPod Nano simply does not have the necessary hardware to support video of any decent quality.
iPod Linux is basically a hack. Apple likes to do things right, and they are off to a great start with the 5th Gen iPod.

I Need to know what is the worst Case Scenario of what will happen if something goes Wrong with the IpodLinux installation... And If It Is Easy to Fix...
Worst case scenario is that you turn your iPod into a little brick. A useless, unrepairable block of plastic and metal.
It's happened to more than ha handful of users in these forums.

If you try it, you should be willing to risk your iPod and the money you spent on it. Keep in mind... even it it does work.. you will have voided your warranty with Apple.

i have linux .. i watch videos on my nano.. its safe because..
u can realy easy do ipod updater wich removes linux from your ipod. believe me its kind of worth it.